HIGH-TEMPERATURE OHMIC CONTACTS TO 3C-SIC GROWN ON SI SUBSTRATES BY CHEMICAL-VAPOR-DEPOSITION

The properties of SiC have great potential for high temperature electr onic device applications. For the realization of these devices the for mation of stable (at elevated temperatures), low resistance ohmic cont acts is required. For this purpose, multiple metallization schemes hav e been investigated on 3C-SiC grown on Si substrates by the chemical v apor deposition method. Both thick layers and thin multilayers of meta ls, deposited by electron beam evaporation, have been studied. Most of the metallizations exhibited ohmic behavior as-deposited even for rel atively low doping levels due to the high concentration of defects in the SiC films. Annealing at temperatures up to 850 degrees C and agein g tests up to 550 degrees C were used to examine their thermal stabili ty. The use of Al as contact overlayer instead of Au resulted in more stable contacts, The Cr/Ti/Pt/Mo/Al metal scheme produced the best res ults. On samples with doping (1-3) x 10(17) cm(-3) an R-c = 5.5 x 10(- 6) Omega cm(2) was obtained while on samples with doping 3 x 10(18) cm (-3) an R-c = 6 x 10(-7) Omega cm(2) before ageing and 7 x 10(-5) Omeg a cm(2) after 400 h at 550 degrees C was observed. (C) 1997 Elsevier S cience S.A.